The objectives of this study are to assess the contributions of category meanings and positions on category lists on the perceptual scale values for those items. Subjects rate differences between stimulus pairs consisting of an electric shock intensity and a word or category number from three distinct seven-point category lists. Perceptual scale values for both the electric shock and category items are determined by Conjoint Measurement analysis. Comparisons of the derived exponents for Steven's power functions for electric shock show that subjects are performing the tasks similarly in three experiments, so comparison of the perceptual scales for the category items is appropriate. Results from these comparisons show that category meanings rather than positions are important in determining perceptial scale values. In addition, subjects estimate the magnitude of sensations evoked by electrical stimulation. Power functions also describe the relation between the numerical judgements and currents. In almost all instances the derived exponents for electric shock determined in the difference estimation experiment were less than those determined in the single-stimulus experiments, consistent with results from other perceptual continua.